1. Field of the Invention
The present invention relates to a technique for applying change processing such as masking and encryption to an object detected in an image.
2. Description of the Related Art
In monitoring systems aiming at abnormal condition observation and criminal prevention of facilities, the use of network cameras for distributing a captured image to a network is increasing. Accordingly, increasing number of network cameras have been installed in public facilities and streets. For example, network cameras are used for advertisement of tourist sites and leisure facilities. These exemplary applications entail privacy protection suitable for a target for disclosing an image.
Japanese Patent Application Laid-Open No. 2004-180236 discusses a technique including: regularly masking an image in an area subjected to privacy protection by changing (or processing) the relevant image signal; and canceling the processing, for example, in the event of fire.
However, when an object relevant to a detected event is to be displayed with the change processing not applied, there may be a situation that the object relevant to the detected event cannot be observed.
For example, the change processing is regularly applied to each of a plurality of human figures in the screen. When carry-away is detected, the change processing is canceled only for a human figure that performed carry-away and the privacy of other human figures are protected. However, if the human figure that performed carry-away cannot be identified, a human figure relevant to the event cannot be observed.
Further, when it takes time since an event occurs until the occurrence of the event is detected, there may be a situation that an object relevant to the event cannot be observed even after the change processing has been canceled in response to the event detection.
For example, when desertion of an object is detected, if a human figure relevant to the desertion (a human figure that performed desertion) has already gone out of the screen, the human figure relevant to the detected event (desertion) cannot be observed.
Further, for example, when carry-away of an object is detected, if a human figure relevant to the carry-away (a human figure that performed carry-away) has already gone out of the screen, the human figure relevant to the detected event (carry-away) cannot be observed.